Aiding device for blind persons



Aug. 17, W43 w. o. SELL AIDING DEVICE FOR BLIND PERSONS Filed March 2'7, 1941 the image are screen shown in Figure 2.

{diagram 'of the" electrical shown in Figure 1.

Patented Aug. 17, 1943 UNITED STATES PATENT QFFICE Amine DEViCE FOR BLIND PER-SONS William '0. Sell, Detroit, Mich. 7 Application March 27, isinseriai Ne. esaszo (or. e'5 '1') Claims.

This invention re ates to devices {for aiding the blind and in particular'to such devices which simulate vision by a corresponding appeal "to one of the other Senses. w 1 V -One object of this invention is to provide a device adapted to produce an impression upon the nervesof an area of the body corresponding toanimagereceivedby'the device. V

Another obj'ect is to provide means for producing an optical irnage of thescen in front of the blind p'e'rsonand converting it into a multiple electrical stimulation of a skin area'on the body of the 'blindperson'corresponding to and changing with the nature of the scene.

Another object is to provi'clea device for aiding blind persons wherein an "optical image of the scene 'in'iront of'theblindperson is focused upon a screen'containin'g inultiple photo-electric cells connected to correspondingmultiple spaced electrodes upon a body plate in circuit with a source of ele'ctricity'of sufficient potential, so'that the optical image pattern upon the screen is translated into an electrical stimulation pattern'upon the portionof the skin of 'theperson to which the body plate is applied.

Another object is to provide a camera obscura focusing an image upon-a screen containing multiple photo-electric'cells connected to corresponding multiple electrodes upon a "body plate and in circuit with a source of relatively high electrical potential so that changes in the nature of immediately converted into changes in the stimulation created bythe multi- 'pleelectrodes'upon the nerves in theskin' of the Figure 1 is a vertical section through the device of this invention.

Figure 2 is a cross section along the line 2--2 in Figure 1, showing the screen with the'multi- 'ple photo electric cells.

Figure 3 is"a'fro nt"elevation of the multiple electrode body plate shown in Figure 1-. I Figured is an enlarged fragmentary elevation of a portion of the multiple photo-electric cell Figure 5 is a diagrammatic view of'a wiring circuit for the device Figure 6 is 'anenlarged fragmentary view of a portion of a modification fot the bod plate fi om that shown in Figure *3.

In general, the device of this invention con- Sitsof a '=C'a1'i"lera;-1ike apparatus, usually known as a camera obscure. having a lens adapted to iocus-anoptical image upon a screen containing a large number 6f tiny photo-electric cells. The latter are preferably of the resistance type, such as selenium "cells, and are connected in circuit with corresponding multiple electrodes mounted upon an insulated body plate which is clamped against the skin of the blind person. The cirrcuitalso contains a source of sufficientl high potential electricity, such as a transformer or spark coil, and a source of low potential electricity such as a battery. A rheostat is inserted in the low tension-circuit'oi the battery to regulate the'strengthofthe sensation. Ah automatic circuit interrupter is alsopreferably included in the circuit in order to make and break the cir- 'c'uit. The lens focusesan'imagepf the scen'e on the 'multiple photo-electric screen and the individual circuits arecompleted'according'to the in tensity of the light fallin upon the particular photo-electric cell, the latter being preferablyof theresi's't'ance type, such as selenium cells. Thus,

the blind person experiences aseries of veryamild shocks from the multiple'electrodes, these shocks corresponding inintensity with'the intensity of the light falling upon the screen. A moving object thus would cast amoving image and a'm'oving stimulation would result on the electrodes of the body plate, thus warning theblind person of the approach of the moving object.

Referring'to the drawing in detail, Figure -1 shows the device of .the invention as consisting 'of acamera .obscu'ra generally designated 19, a "body: electrode plate generally designated H, and an electrical energy casing generally designated FZ-andsecur'edtothe camera obscurerllJ. The

latter includes a box-like'casing l3 having an aperture Main the front wall t4 thereof containing. an *objective lens I-5 held in position by the rovided with at'op'l'b'a bottom 18, side walls I9 and 20, anda rear wall '2l. --A casing handle '"22 is-secured"as"at'23"to the top wall 11.

Mounted "at the principal ifocus of the objective "lens'l5is a multiple photo-electric cell screen generally designated '24 "which may be' concisely termed "a photo-cell screen. The photo-eell screen 24 preferably consists of a plate 25 of conducting material having a plurality of photoelectric cells generally designated 25 mounted close together of substantially the entire screen, or the portion thereof on which the image is cast by the objective lens system I5.

Each photo-electric cell 26 consists of a central electrode 27 mounted in a bore 28 in an insulating plug 29, which in turn is mounted in a bore 33 in the conducting plate 25. Theend of the plug 23 is countersunk slightly beneath the front surface iii of the conducting plate 25, thus forming an annular recess for a photo-electric elehaving an insulating plate 34 with spaced bores 35 in which the electrodes 33 are arranged. The eflective electrodes 33 are provided with tapered contact tips 35 for engagement with the skin 37 of the blind person so that the end of each electrode will engage a relatively small area of the users body.

The insulating plate 34 of the body plate II is also provided with a plurality of spaced bores 38 in which are mounted spaced indifferent electrodes 39 likewise having tapered tips spaced apart from the tapered tips 35 of electrodes 33 and simi "ly in engagement with the skin of the The eifective electrodes 33 and indifferent electrodes 33 can be spaced various distances depending upon the sensitivity of the. nerves in various portions of the body. The poles 2'! and electrodes 33 are connected by the conductors III whereas the indifferent electrodes 39 are themselves interconnected by the conductors 42 common to all of the electrodes 39. The conductors 2'! are contained in a cable 43 which extends through holes 44 and 5 3 in the back wall 2| and cover plate 36 of the casing. I3 and body plate II respectively. The cover, member 46 protects the exposed ends of the electrodes at the back of the plate 34. v

The electrical circuit containing the photoelectric cells 25 and effective electrodes 33 and indifferent electrodes 39 are energized by devices mounted within the lower casing i2 and containing a battery 4? or other suitable source of elec- I o-f the battery II? is connected by the line 54 to the spark coil 52. In particular, the conductor -35 is connected to the adjusting arm 55 of the rheostat the resistance element 55 of which is connected by the conductor 5| to the vibrating arm 5'. of the automatic circuit interrupter 58 which also includes an adjustable contact 59 threaded through a mount 55 which is connected by the conductor 5! to one pole of the primary winding 52 being connected to the conductor 54. One pole of the secondary winding 63 of the spark coil is connected by the conductor 35 to the conductor 32 interconnecting the electrodes 39.

The rheostat 5!! is adjusted by a knob 55 projecting through a hole 6! in the front of'the lower casing i 2 and the secondary leads 54 and val .tery 47, will 65 f the spark coil 52 pass upwardly through apertures 68 and 69 respectively in the bottom wall I8 of the casing I3. The lower casing I2 is preferably hinged as at 13 to the rear wall 2| of the upper casing I3 and is releasably secured in place by the latch 'II connecting it to the front wall I I of the casing I3.

The body plate II is provided with belt loops :2 and 73' at its opposite edges for the attachment of belt portions I4 and I5. By means 01' the latter the body plate II may be clamped to an area of the skin in any convenient location. The spacing of the electrodes 33 and 39 may be varied to suit the particular portion of the body to which the electrode is applied, and this in turn, naturally depends upon the relative distribution and concentration of the nerve endings in the skin.

The modification shown in Figure 6 shows a. body plate III including an insulating plate I34 having effective electrodes I33 therein corresponding to the photo-electric cell effective electrodes 33 in the principal form of the invention. Surrounding the electrodes I 33 are annular indifferent electrodes I39. corresponding to the indiiferent electrodes 39 and similarly interconnected by the conductors I42. The annular electrodes I39 having the advantage of localizing the sensations by entirely surrounding the electrodes I 33 so that the current will be confined within theindifferent annular electrodes only and not radially to three or more indifferent electrodes in the form ofthe invention shown in Figures 1 to 5 inclusive. The annular electrodes I38 also serve somewhat to localize the effect of perspiration, which might otherwise short-circuit the various electrodes. The electrical connections of the electrodes I33 and I33 are the same as those described above for the electrodes 33 and 39, and the operation is similar.

In the operation of the invention, the blind person clamps the body plate I I against his skin at any suitable location and adjusts the knob 66 of the rheostat 58 until the electrical sensations produced between the electrode tips 36 and 40 are strong enough to be sensitively perceived. When the'blind person aims the casing I3 in the direction which he wishes to scan, the lens I5 casts an image of the scene upon the multiple photo-electric cellscreen 24. The intensity of light in this image will vary and accordingly the diiferent photo-electric cells 2 5 will vary in resistance and will accordingly transmit different amounts of electricity. The current flowing through the primary circuit, including the batthus be differently discharged through the secondary circuit including the photo-electric cells 26 and electrodes 33 and 33, those photo-cells on which the more intense light falls passing a more powerful electrical discharge to their electrodes. The user therefore experiences a tinglingsensation between the various electrodes, and by the varying nature of this tingling sensation, he is enabled to interpret the nature of the scene before him, particularly afterhe has had sufiicient practice With the apparatus. The blind person can interpret the approach or passing of a moving object, such as an automobile, by the changing of the sensation from point to point in the-area covered by the body plate I I,

assuming that the camera obscura I0 is held stationary at the time. 7 r 1 V The rheostat 55 may beof the type which also serves as a switch, or a switch "I6, such as a push-button switch, may be inserted in the primeans for translating. said image into electrical impulses, a dielectric plate providing an electrode support to be positioned adjacent the body, and a plurality of slightly separated electrodes on said support engaging the skin of the person for applying said impulses to the nervous system of the body. 7

2. In an aiding device for blind persons, optical means for forming an image, photo-electric means for translating said image into electrical impulses, a dielectric plate providing an electrode support to be positioned adjacent the body, and a plurality of slightly separated electrodes mounted on the support and connected to said photo-electric means for applying said impulses to the nerves in the skin of the person.

3. In an aiding device for blind persons, a lens system arranged to form an image, a screen with multiple photo-electric cells arranged to receive and translate said image into multiple electrical impulses, a dielectric plate providing an electrode support to be positioned adjacent the body, and a plurality of slightly separated electrodes carried by said support engageable with the skin of the person for applying said impulses to the nervous system of the body.

4:. In an aiding device for blind persons, a lens system arranged to form an image, a screen with multiple photo-electric cells arranged to receive said image, said cells being variable in electrical resistance in response to the falling of light thereon, a dielectric plate providing an electrode support to be positioned adjacent the body, a plurality of slightly separated electrodes for contacting the skin carried by said support connected to said photo-electric cells, and an open electric circuit arranged to pass electricity through said cells and electrodes, when closed as by the skin of the blind person.

5. In an aiding device for blind persons, a lens system arranged to form an image, a screen with a plurality of equidistantly spaced photoelectric cells arranged to receive said image, said cells being variable in electrical resistance in response to the falling of light thereon, a plurality of efiective electrodes respectively connected to said photo-electric cells, a series of indifierent electrodes adjacentbut spaced apart from said first-mentioned electrodes, means for applying said electrodes to'the skin of the blind person, and means for passing electric current through said cells and between said electrodes by way of the skin of the blind person.

6. In an aiding device for blind persons, a lens system arranged to form an, image, a screen with a plurality of photo-electric cells arranged to receive said image, said cells being variable in electrical resistance in response to the falling of. light thereoma body plate engageable with the skin of the blind person and having a plurality of effective electrodes respectively connected to said photo-electric cells and a plurality of indifferent electrodes adjacent to but spaced apart from said effective electrodes, and means fOr passing electric current through said cells and between said electrodes by way of the skin of the blind person.

'7. In an aiding device for blind persons, a lens system arranged to form an image, a screen with a plurality of photo-electric cells arranged to receive said image, said cells being variable in electrical resistance in response to the falling of light thereon, a body plate engageable with the skin or the blind person and having effective electrodes respectively connected to said photo-electric cells and independent electrodes adjacent to but spaced apart from said main electrodes, and means'including a high tension electric circuit for passing electric current through said cells and between said electrodes by Way of the skin of the blind person.

8. In an aiding device for blind persons, a lens system arranged to form an image, a screen with a plurality of photo-electric cells arranged to receive said image, said cells being variable in electrical resistance in response to the falling of light thereon, a body plate engageable with the skin of the blind person and having a plurality of spaced efiective electrodes respectively connected to said photo-electric cells and independent electrodes adjacent to but spaced apart from said effective electrodes, an electrical induction coil including a secondary high tension circuit connected to said photo-electric cells and to said electrodes and a primary low tension circuit associated therewith, and means for energizing said low tension circuit.

9. In an aiding device for blind persons," optical means for forming an image, photo-electric means for translating said image into electrical impulses, and means connected to said photoelectric means for applying said impulses to the nerves of the skin of the blind person and including a plurality of effective electrodes and indifferent electrodes spaced apart from said main electrodes.

10. In an aiding device for blind persons, optical means for forming an image, photo-electric means for translating said image into electrical impulses, and means connected to said photoelectric means for applying said impulses to the nerves of the skin of the blind person and including a plurality of spaced effective electrodes and indifferent electrodes spaced apart from said effective electrodes, certain of said indifferent electrodes substantially encircling the effective electrodes adjacent thereto.

WILLIAM O. SELL. 

